1,271 research outputs found

    Genetic transformation of Physcomitrella patens mediated by Agrobacterium tumefaciens

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    A simple efficient protocol for introducing exogenous gene from Agrobacterium tumfaciens into Physcomitrella patens was established. When the gametophores of gametophytes about 12 leaves wereinoculated into the wells of PP3 medium at 25°C under the continuous light energy of 30 mol m-2 s-1 from cool-white fluorescent lamps, they grew up to form many buds at about 11 days, then A. tumefaciens at OD600 0.3 was added into the whole wells for 4 times at an interval of 12 h for continuous co-cultivation. After about 17 days of co-culture, the new juvenile gametophytes about 12 leaves grew up and were incubated into PP3 medium containing 50 mg L-1 kanamycin for selection. 100% positiveplants could be obtained after 4 generations of selective culture. PCR analysis showed that gene Cameleon YC2.1 in A. tumefaciens was transferred into all detected plants of P. patens and southern blotting analysis confirmed that exogenous gene was integrated into genomic DNA at a single locus. The results facilitated to analyze genes from more plants via genetic transformation by this system

    Improving corporate governance in state-owned corporations in China: which way forward?

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    This article discusses corporate governance in China. It outlines the basic agency problem in Chinese listed companies and questions the effectiveness of the current mechanisms employed to improve their standards of governance. Importantly, it considers alternative means through which corporate practice in China can be brought into line with international expectations and stresses the urgency with which this task must be tackled. It concludes that regulators in China must construct a corporate governance model which is compatible with its domestic setting and not rush to adopt governance initiatives modelled on those in cultures which are fundamentally different in the hope of also reproducing their success

    Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

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    Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

    Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

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    The decay channel ψπ+πJ/ψ(J/ψγppˉ)\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) is studied using a sample of 1.06×1081.06\times 10^8 ψ\psi^\prime events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the ppˉp\bar{p} invariant mass spectrum. The enhancement can be fit with an SS-wave Breit-Wigner resonance function with a resulting peak mass of M=186113+6(stat)26+7(syst)MeV/c2M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2 and a narrow width that is Γ<38MeV/c2\Gamma<38 {\rm MeV/}c^2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

    Primary small cell carcinoma of the esophagus: clinicopathological and immunohistochemical features of 21 cases

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    BACKGROUND: Primary small cell carcinoma (SCC) of the esophagus is a rare and aggressive tumor with poor prognosis. In this study, we report the clinicopathological characteristics of 21 cases of small cell carcinoma of the esophagus treated at the Cancer Center of Sun Yat-Sen University, with particular focus on the histologic and immunohistochemical findings. METHODS: Twenty-one patient records were reviewed including presenting symptoms, demographics, disease stage, treatment, and follow-up. Histologic features were observed and immunohistochemical detection of cytokeratin (CK), epithelial membrane antigen (EMA), neuron specific enolase (NSE), synaptophysin (Syn), chromogranin A (CgA), neuronal cell adhesion molecules (CD56), thyroid transcriptional factor-1 (TTF-1) and S100 protein (S100) was performed. RESULTS: The median age of patients in the study was 56 years, with a male-to-female ratio of 3.2:1. Histologically, there were 19 "homogenous" SCC esophageal samples and 2 samples comprised of SCC and well-differentiated squamous cell carcinoma. The percentages of SCC samples with positive immunoreactivity were Syn 95.2%, CD56 76.2%, TTF-1 71.4%, NSE 61.9%, CgA 61.9%, CK 57.1%, EMA 61.9%, and S100 19.0%, respectively. The median patient survival time was 18.3 months after diagnosis. The 2-year survival rate was 28.6%. CONCLUSION: Our study suggests that esophageal SCC has similar histology to SCC that arises in the lung compartment, and Chinese patients have a poor prognosis. Higher proportion of positive labeling of Syn, CD56, CgA, NSE, and TTF-1 in esophageal SCC implicate that they are valuably applied in differential diagnosis of the malignancy

    Specification and guideline for technical aspects and scanning parameter settings of neonatal lung ultrasound examination

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    Lung ultrasound (LUS) is now widely used in the diagnosis and monitor of neonatal lung diseases.Nevertheless, in the published literatures,the LUS images may display a significant variation in technical execution,while scanning parameters may influence diagnostic accuracy.The inter- and intra-observer reliabilities of ultrasound exam have been extensively studied in general and in LUS.As expected,the reliability declines in the hands of novices when they perform the point-of-care ultrasound (POC US).Consequently,having appropriate guidelines regarding to technical aspects of neonatal LUS exam is very important especially because diagnosis is mainly based on interpretation of artifacts produced by the pleural line and the lungs.The present work aimed to create an instrument operation specification and parameter setting guidelines for neonatal LUS.Technical aspects and scanning parameter settings that allow for standardization in obtaining LUS images include (1)select a high-end equipment with high-frequency linear array transducer (12-14 MHz).(2)Choose preset suitable for lung examination or small organs.(3)Keep the probe perpendicular to the ribs or parallel to the intercostal space.(4)Set the scanning depth at 4-5 cm.(5)Set 1-2 focal zones and adjust them close to the pleural line.(6)Use fundamental frequency with speckle reduction 2-3 or similar techniques.(7)Turn off spatial compounding imaging.(8)Adjust the time-gain compensation to get uniform image from the near-to far-field

    High Proportion of 22q13 Deletions and SHANK3 Mutations in Chinese Patients with Intellectual Disability

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    Intellectual disability (ID) is a heterogeneous disorder caused by chromosomal abnormalities, monogenic factors and environmental factors. 22q13 deletion syndrome is a genetic disorder characterized by severe ID. Although the frequency of 22q13 deletions in ID is unclear, it is believed to be largely underestimated. To address this issue, we used Affymetrix Human SNP 6.0 array to detect the 22q13 deletions in 234 Chinese unexplained ID patients and 103 controls. After the Quality Control (QC) test of raw data, 22q13 deletions were found in four out of 230 cases (1.7%), while absent in parents of the cases and 101 controls. A review of genome-wide microarray studies in ID was performed and the frequency of 22q13 deletions from the literatures was 0.24%, much lower than our report. The overlapping region shared by all 4 cases encompasses the gene SHANK3. A heterozygous de novo nonsense mutation Y1015X of SHANK3 was identified in one ID patient. Cortical neurons were prepared from embryonic mice and were transfected with a control plasmid, shank3 wild-type (WT) or mutant plasmids. Overexpression of the Y1015 mutant in neurons significantly affected neurite outgrowth compared with shank3 WT. These findings suggest that 22q13 deletions may be a more frequent cause for Chinese ID patients than previously thought, and the SHANK3 gene is involved in the neurite development

    The Spin Structure of the Nucleon

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    We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

    Organochlorine Pesticides in Consumer Fish and Mollusks of Liaoning Province, China: Distribution and Human Exposure Implications

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    Fish and mollusk samples were collected from markets located in 12 cities in Liaoning province, China, during August and September 2007, and 22 organochlorine pesticides (OCPs) were detected. DDT, HCH, endosulfan, chlordane, and HCB were the dominating OCPs, with mean concentrations and ranges of, respectively, 15.41 and 0.57 to 177.56 ng/g, 0.84 and below detection limit (BDL) to 22.99 ng/g, 1.31 and BDL to 13.1 ng/g, 1.05 and BDL to 15.68 ng/g, and 0.63 and BDL to 9.21 ng/g in all fish and mollusk samples. The concentrations of other OCPs generally were low and were detectable in a minority of samples, reflecting the low levels of these OCPs in the study region. In general, OCP concentrations were obviously higher in fish than in mollusks, and higher in freshwater fish than in marine fish, which indicated, first, that freshwater fish are more easily influenced than seawater fish and mollusks by OCP residues in agricultural areas and, second, that there are different biota accumulation factors for OCPs between fish and mollusk. To learn the consumption of fish and mollusk, 256 questionnaires were sent to families in 12 cities of Liaoning province. Using the contamination data, average estimated daily intakes of OCPs via fish and mollusk consumption were calculated, which were used for exposure assessment. The public health risks caused by exposure to OCPs in the course of fish and mollusk consumption were compared to noncancer benchmarks and cancer benchmarks

    Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

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    The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition
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